In one embodiment, a method for forming a titanium nitride barrier material on a substrate is provided which includes depositing a titanium nitride layer on the substrate by a metal-organic chemical vapor deposition (MOCVD) process, and thereafter, densifying the titanium nitride layer by exposing the substrate to a plasma process. In one example, the MOCVD process and the densifying plasma process is repeated to form a barrier stack by depositing a second titanium nitride layer on the first titanium nitride layer. In another example, a third titanium nitride layer is deposited on the second titanium nitride layer. Subsequently, the method provides depositing a conductive material on the substrate and exposing the substrate to a annealing process. In one example, each titanium nitride layer may have a thickness of about 15 Å and the titanium nitride barrier stack may have a copper diffusion potential of less than about 5×1010 atoms/cm2.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method for forming a titanium nitride barrier stack on a substrate, comprising: depositing a first titanium nitride layer on the substrate by a metal-organic chemical vapor deposition process; densifying the first titanium nitride layer by exposing the substrate to a plasma process; depositing a second titanium nitride layer on the first titanium nitride layer by the metal-organic chemical vapor deposition process; densifying the second titanium nitride layer by exposing the substrate to the plasma process; depositing a conductive material on the substrate; and exposing the substrate to an annealing process, wherein the titanium nitride barrier stack has a copper diffusion potential of less than about 5×10 10 atoms/cm 2 .
2. The method of claim 1 , wherein the copper diffusion potential is less than about 1×10 10 atoms/cm 2 .
3. The method of claim 1 , further comprising: depositing a third titanium nitride layer on the second titanium nitride layer by the metal-organic chemical vapor deposition process; and densifying the third titanium nitride layer by exposing the substrate to the plasma process.
4. The method of claim 3 , wherein the first titanium nitride layer has a thickness of about 15 Å or less, the second titanium nitride layer has a thickness of about 15 Å or less, and the third titanium nitride layer has a thickness of about 15 Å or less.
5. The method of claim 1 , wherein the substrate is exposed to a plasma gas during the plasma process, the plasma gas comprises hydrogen and a gas selected from the group consisting of nitrogen, argon, helium, neon, and combinations thereof.
6. The method of claim 5 , wherein each of the titanium nitride layers is exposed to the plasma for a time period within a range from about 10 seconds to about 20 seconds and at a plasma power within a range from about 750 watts to about 1,250 watts.
7. The method of claim 1 , wherein the annealing process occurs for a time period within a range from about 30 minutes to about 90 minutes and at a temperature within a range from about 350° C. to about 500° C.
8. The method of claim 1 , wherein the titanium nitride barrier stack is deposited on a metallic titanium layer disposed on the substrate, and the metallic titanium layer is deposited on the substrate by a physical vapor deposition process.
9. The method of claim 8 , wherein the conductive material comprises an element selected from the group consisting of copper, tungsten, aluminum, titanium, tantalum, ruthenium, cobalt, alloys thereof, and combinations thereof.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
October 9, 2007
April 21, 2009
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